Oct.1 19561 WM. H. PARTRIDGI, Brazilian Merganser 487 Crested Eagles were found by us many times along the Urugua-i River. Giai (1951: 256) reports the Black-and-White Crested Eagle preying upon the mergansers. ACKNOWLEDGEMENTS I am grateful to Dr. Erwin Stresemann for helpful information concerning specimens in the Berlin Museum and to Dr. J. B. Esteban for information about a specimen in the Miguel Lillo Institute of Tucumfn University (Tucumfn, Argentina). I am indebted to Prof. F. Gneri of the Buenos Aires Museum for data on the fish eaten by the Brazilian Merganser. I wish to express my gratitude to Dr. Philip S. Humphrey for editing the manuscript of the present article. SUMMARY The Brazilian Merganser was rediscovered in Misiones (Argentina) in 1947; up to that time the species had been considered close to ex- tinction. The available locality records indicate that the Brazilian Merganser is restricted to southeastern Brazil and the neighboring regions of Paraguay and Argentina. In Misiones the Brazilian Merganser is not rare but has been found only along the small rivers and streams that flow from the highlands in the interior of the province into the Alto Parant, which is a tributary of the La Plata River. The Brazilian Merganser lives in the wildest parts of these small rivers and has never been found on the Alto Parani itself. Brazilian Mergansers are sedentary birds and probably spend their entire lives along a small part of one river. The species is nonmigratory and the pairs appear to stay together throughout the year. The feeding grounds of the Brazilian Merganser are along the rapids. They dive for their food which consists mainly of fish up to 19 centimeters in length. The breeding season begins in June. Incubation occurs in July and August. Downy young have been found in August. The first and only nest discovered was in the hollow limb of a tree and was 25 meters above the water level. Four black and white downy young left the nest on August 30, 1954. Probably the most dangerous enemy of the Brazilian Merganser in Misiones is the Black-and-White Crested Eagle (Spizastur melanoleucus).